Single Crystal Growth of Metal Oxides and Metal-Organic Coordination Complexes and Their Analyses
Date Issued
2012
Date
2012
Author(s)
Shen, Chin-Chang
Abstract
In this thesis, we study the single crystal growth of metal oxides and metal -organic coordination complexes. To produce metal oxides, we use the flux method to grow multiferroic TbMnO3 and phosphoric LiSrPO4 single crystals. To produce metal -organic coordination complexes, we use the hydrothermal method to grow the phosphors Zn2Cl4(μ-bipy)2 and Zn2(IM)4•(DMF) .
In Chapter 1, we review the growth methods for solid materials and demonstrate the corresponding properties and applications of the resulting products. The targets of this study are also described. In Chapter 2, we introduce the experimental procedures for crystal growth, as well as the characterization techniques, used in this study.
The third chapter focuses on TbMnO3 crystal growth and characterization of the resulting crystals. TbMnO3 has a distorted perovskite structure with spontaneous polarization. Gigantic magneto-electric and magneto- capacitive effects, which may switch polarization by magnetic fields, are also found in TbMnO3.
The fourth chapter discusses the growth of LiSrPO4. Rare earth Eu2+-doped LiSrPO4 has excellent near-UV absorption and blue-light emission that can be applied in UV-LEDs. The X-ray diffraction (XRD) pattern reported for LiSrPO4 is inconsistent with JCPDS No 053-1238 and 140-202. We find a suitable flux in which to grow LiSrPO4 single crystals. LiSrPO4 crystallizes to form a hexagonal structure with a space group of P65 and cell parameters a = 5.0040(2) Å, c = 24.6320(16) Å, V = 534.15(5), and Z = 6. The LiSrPO4 unit cell is composed of LiO4 and PO4 tetrahedra that form a three-dimensional LiPO42- anionic framework. This framework has a spiral-type helical channel structure along the c axis where Sr2+ cations are located.
In the fifth chapter, we study organic metallic phosphors grown using the hydrothermal method to synthesize a metal-organic framework for Zn2Cl4(µ-bipy)2. The structure of the framework is determined by single-crystal XRD refinement. The Zn2Cl4(µ-bipy)2 coordination compound is a near-UV excitable phosphor. This compound is capable of producing white light as a single component.
In the sixth chapter, a polymorph of Zn2(IM)4•(DMF) (IM: imidazolate; DMF: dimethyl formamide) frameworks is synthesized using a DMF template. The topology of the ZnN4 framework is similar to that of zeolite, with a chain of connected SiO4 tetrahedra. This polymorph has a zeolite-like structure and a wave-shape topology in the [010] direction. The main chain is connected to an IM ligand. The framework structure has excellent chemical and thermal stability. The framework also exhibits broad near-UV excitation ranging from 350 nm to 430 nm. Broadened photoluminescence emission is observed at 445 nm. This framework has great potential as a phosphor for applications in near-UV or UV white LEDs.
We conclude our study in Chapter 7.
Subjects
Metal Oxide
Metal-Organic Coordination Complex
Single Crystal Growth
Type
thesis
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